Kuch nahi hota, Loco k compresser se Break pressure maintain kiya jata hai. Jaise se coaches alag ho jaate, Air pressure kum hota or Brakes apply ho jata. Agar aisa uphill or down hill the gradient hota tab fatal hota. Waise CBC coupling me decoupling ki sikayat hoti hai, kuch din pehle kisi U.P bound train k sath bhi aisa hua that.